High voltage switching transistors, such as power MOSFETs, junction field effect transistor (JFETs) and gallium nitride (GaN) high electron mobility transistor (HEMT), are commonly used as semiconductor switches in high voltage and high power devices such as switched-mode power supplies, motor controllers, and high voltage and high power switching circuits. Some of these devices, such as the GaN HEMT have the ability to be operated at very high voltages without the device breaking down or becoming damaged.
In many applications, a high voltage switching transistor is driven by a specialized driving circuit that produces switching voltages that are appropriate both for the particular application and for the particular technology of the switching transistor being driven. For example, a high side switching transistor that is referenced to a high voltage power supply node will often include a level shifting circuit that converts a ground referenced logic input level to a drive signal that is appropriately referenced to the high voltage power supply and has voltage levels that turns the high side switching transistor on and off.
A few parameters that specify the performance of high voltage switching transistor systems include turn-on time, turn-off time, blocking voltage, on-resistance and power consumption. In the design of systems that utilize high voltage switching transistors, there is often a tradeoff involved among these parameters. For example, in high voltage switching transistors that have a very high blocking voltage and low on-resistance, there is often a corresponding high input capacitance that results in higher power consumption when the high voltage switching transistor is driven in a manner to achieve fast turn-on and turn-off times.